iftikhar ahmed

Hi friends;

I want to buit laser beam contactless tachometer. any one have source code,schematic,or other related material about it. Please share it.

THANKS IN ADVANCE

Ayne

I also want to ask some thing from experts..

sensor --- ? ---- microcontroller.
What we use in between sensor and microcontroller??? opamp???

basic idea i know
1. there will be a light source.
2. a reflector on rotating shaft(or may be something other), that will reflect light coming from source.
3. a opto sensor for sensing reflected light, photodiode cuz it is only available in our local market.
4. some circuitry that take input from sensor and convert it into reasonable singnal that can be use with microcontroller. but i don't know much about this part. explanation needed.
5. A microcontroller, it will count input pulses coming from sensor for a given time and convert it into Round/Minute, and will display on our desired display.

Am i right if not then plz guide me.
thanks.

iftikhar ahmed

Thanks Ayne
I think the idea is correct.But the broblem is that how i get reflected light that give one pulse per revuolution. What about this laser reflecting material.

Pommie

What do you want to measure the speed of?

Model aircraft fliers use a contactless RPM meter which simply counts light pulses caused by the shadow of the propeller.

Other sensors will work with simple black and white paint. Have a look at this page. It describes a line following robot but the circuitry for detecting light/dark is the same.

Mike.

iftikhar ahmed

thanks mike.

I want to meseure speed of motor shaft with contactless method by using pic

ericgibbs

hi,
You can buy self adhesive reflective strip, clean the shaft and adhere the strip along the shaft.

If you want to improvise, use a piece of aluminium kitchen foil.

Depending on the diameter of the shaft and the distance you want to space your detector away from the reflector, you can buy small red or clear reflectors from a local cycle/car shop.

If your shaft rotational speed isn't to high, you can use a small linear permanent magnet on the shaft, operating a reed switch.
Just have a simple RC filter on a +5v system.

Regards
EricG

iftikhar ahmed

thanks, EricG

iftikhar ahmed

I need Encyclopedia of Electronics Circuits, Volume 5, Any one .please share it to me.

THANKS in advance